WATCH: Amtrak Train Derailment Video Over I-5 Near Tacoma

An Amtrak train dramatically derailed over Interstate I-5 near Tacoma, Washington on December 18, 2017, although it was not yet clear how many people were injured or to what degree.

A dramatic video circulated on social media of the derailment in Washington State. You can watch it here:

According to the State of Washington Department of Transportation, “The derailment happened on Interstate 5 near Mounts Road in Pierce County, Washington.” Although some reporters said the derailed train was being treated as a possible mass casualty event, it was not yet clear whether anyone had died. However, the images that emerged from the scene showed the crumpled train lying over the busy Interstate, where it caused a major traffic jam. The cause of the derailment is not yet clear.

According to KIRO7, some injuries were reported and an airlift was on the way to the scene. All lanes of the busy I-5 freeway were blocked, according to the Seattle television station. “Amtrak is aware of an incident with Train 501, Cascades service from Seattle to Portland. Emergency services are on the scene and Amtrak management is responding,” the television station reported.

The train operated at high speeds. “High speed Amtrak train hanging over I-5 at Mounts road. First responders are treating this as a mass casualty incident, but no official word on injuries yet,” KIRO-7 reported.

According to the Seattle Times, the train, known as the 501, was in its inaugural run, and fell off a bridge between Lakewood and Olympia, Washington.